#!/usr/bin/env python3
#
#  decorators.py
"""
reStructuredText XRef role for decorators.

.. versionadded:: 0.9.0
.. extensions:: sphinx_toolbox.decorators


Usage
------

.. rst:role:: deco

	Adds a cross reference to a decorator, prefixed with an ``@``.

	.. rest-example::

		.. decorator:: my_decorator

			A decorator.

		:deco:`my_decorator`

		:deco:`@my_decorator`

		:deco:`Title <my_decorator>`


.. latex:clearpage::


API Reference
----------------

"""
#
#  Copyright © 2020-2021 Dominic Davis-Foster <dominic@davis-foster.co.uk>
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#  OR OTHER DEALINGS IN THE SOFTWARE.
#
#  Based on Sphinx
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# stdlib
from typing import Tuple, Type  # noqa: F401

# 3rd party
from docutils.nodes import Element
from sphinx.application import Sphinx
from sphinx.domains.python import PyXRefRole
from sphinx.environment import BuildEnvironment

# this package
from sphinx_toolbox.utils import SphinxExtMetadata, metadata_add_version

__all__ = ("PyDecoXRefRole", "setup")


class PyDecoXRefRole(PyXRefRole):
	"""
	XRef Role for decorators members.
	"""

	def process_link(
			self,
			env: BuildEnvironment,
			refnode: Element,
			has_explicit_title: bool,
			title: str,
			target: str,
			) -> Tuple[str, str]:
		"""
		Called after parsing title and target text, and creating the reference node (given in ``refnode``).

		This method can alter the reference node and must return a new (or the same) ``(title, target)`` tuple.

		:param env:
		:param refnode:
		:param has_explicit_title:
		:param title:
		:param target:
		"""

		target = target.lstrip('@')

		title, target = super().process_link(
			env=env,
			refnode=refnode,
			has_explicit_title=has_explicit_title,
			title=title,
			target=target,
			)

		if not has_explicit_title and not title.startswith('@'):
			title = f"@{title}"

		# Ensure the reference is correctly found in the broader scope.
		refnode["reftype"] = "obj"

		return title, target


@metadata_add_version
def setup(app: Sphinx) -> SphinxExtMetadata:
	"""
	Setup :mod:`sphinx_toolbox.decorators`.

	:param app: The Sphinx application.
	"""

	app.add_role_to_domain("py", "deco", PyDecoXRefRole())

	return {"parallel_read_safe": True}